Soils

Sierra Leone is situated in the humid tropics on the west coast of Africa. It consists of four broad physiographic regions: the Peninsula Mountains, the Coastal Plain, the Interior Plain and the Interior Plateaux and Hill Region. Each of these broad physiographic regions is subdivided into soil provinces on basis of differences in soil forming factors given a total of 16 Soil Provinces.

Soil Types within the Transmission Line Buffer

To acquire the soil types crossed by the CLSG transmission, three buffers (400 m, 600 m, and 1,000 m) were delineated along the transmission line using GIS. The soil dataset was clipped with the buffers and various soil types within the transmission line buffers were then extracted. However, the area that will be affected varies among the 400m, 600m, and 1,000 m buffer ranges. The following nine soil types were extracted with the various transmission line buffers:

Activities with Potential to Impact Soils

The main impacts on soils are likely to arise during the various site preparation and construction activities associated with the TRANSCO CLSG project. However, soils will also be vulnerable during the operation and maintenance phases. Project activities with the greatest potential to impact soils include clearing and grubbing of vegetation for transmission line ROW and access roads, excavation for tower and substation foundations, and ongoing operations and maintenance.

Potential Soil Pollution Types within the Project Area

The potential soil pollution types identified within the Project area include: soil erosion due to loss of vegetation; soil compaction due to the movement of heavy vehicles and machinery, and Soil contamination from the use of improper handling, and spills of hazardous materials, such as insulating oils, wood preservatives, paints, herbicides/pesticides, and other toxic substances which could be used during the construction, operation, or maintenance of the project.

Areas Likely to be Polluted

The areas likely to be polluted are areas where there is active construction, installation, storage and maintenance activities. These areas include the substation and the construction storage sites and the possible pollutants are lubricants and fuel.